1. Field of the Invention
The present invention relates to an apparatus which can record information on and reproduce information from a recording and reproducing disc, and more particularly, to a method of verifying that a disc recording and reproducing apparatus normally generates or updates defect management area (DMA) information of a disc, and a test apparatus for performing the same.
2. Description of the Related Art
A recording and reproducing disc is an optical disc, which information is recorded on and reproduced from using light such a laser beam, for example, a digital versatile disc random access memory (DVD-RAM). A DVD-RAM is a rewritable disc. According to xe2x80x9cDVD Specifications for Rewritable Disc Part1 Physical Specifications Version 2.0,xe2x80x9d DVD-RAM includes four DMAs, i.e., DMA1, DMA2, DMA3 and DMA4, on each side thereof for managing the defects thereon.
As shown in FIG. 1, DMA1 and DMA2 are located in a lead-in area near the inner diameter of a disc, and DMA3 and DMA4 are located in a lead-out area near the outer diameter of the disc. Each DMA is followed by a reserved sector.
A disc definition structure (DDS), a primary defect list (PDL) and a secondary defect list (SDL) are stored in the DMA. A DDS includes information on the format structure of a disc, for example, a disc certification flag, a DDS/PDL update counter and a start logical sector number of each zone. A PDL includes information on all defective sectors detected on the disc during initialization of the disc. An SDL includes information on the sector number of each first sector in defective blocks (error-correction code (ECC) blocks) occurring while the disc is in use, information on the sector number of each first sector in spare blocks used to replace defective blocks and information on a spare area.
Some information included in the DMA can be immediately read and used. On the other hand, the DMA includes information which varies with the positions and the number of defects on a disc. In addition, some information, for example, the position information of the start sector number of each zone or the position information of a logical sector number 0, can be obtained by performing an algorithm based on defect information registered in the DMA.
Four DMAs exist on each side of a disc to prevent erroneous defect management due to errors in the DMA information. Since such DMA information is closely related to a physical data sector, a recording medium such as a movable optical disc may not be compatible with two different disc recording and reproducing apparatuses when the DMA information is incorrectly written or read.
This is because, when the recording and reproducing architecture of a disc recording and reproducing apparatus (for example, a DVD-RAM recording and reproducing apparatus) is divided into a file system layer, a host interface layer for interfacing a host computer with the recording and reproducing apparatus, a physical disc recording and reproducing apparatus (or disc drive) layer for recording and reproducing physical signals, and a recording medium layer, writing and reading of DMA information is performed in the physical disc recording and reproducing apparatus layer and the layers therebelow.
In an actual file system, user information to be recorded or reproduced is transmitted to a disc recording and reproducing apparatus based on only a logical sector number, and the disc recording and reproducing apparatus converts the logical sector number into a physical sector number to record or reproduce the user information. In this case, DMA information is used. Accordingly, when the DMA information has erroneously been read or written in a given disc recording and reproducing apparatus, data cannot be correctly read or written in another recording and reproducing apparatus.
Accordingly, a method of verifying that a disc recording and reproducing apparatus correctly reads DMA information recorded on a disc and correctly records DMA information on the disc for generation or update of DMA information is desired.
To solve the above problem, a first object of the present invention is to provide a method of verifying that defect management area (DMA) information is generated or updated normally when a disc recording and reproducing apparatus performs reinitialization with secondary defect list (SDL) conversion without certification.
A second object of the present invention is to provide a method of verifying that the DMA information of a disc, which is generated using a blank disc and a test reference DMA mirror file configured such that every kind of defect information is included in a primary defect list, is generated or updated normally when a disc recording and reproducing apparatus performs reinitialization with SDL conversion without certification.
A third object of the present invention is to provide a test apparatus for verifying that DMA information is generated or updated normally when a disc recording and reproducing apparatus performs reinitialization with SDL conversion without certification.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects of the present invention, there is provided a method of verifying the DMA information generation or updating function of a recording and reproducing apparatus, which records information on or reproduces information from a disc with DMA information. The method includes performing reinitialization without certification in the recording and reproducing apparatus using a test disc with test reference information and generating test information from the defect management information which is generated after the reinitialization, and comparing reference information expected from the test reference information with the test information and providing the result of verification of the test information.
To achieve the above and other objects of the invention, there is also provided an apparatus for testing the DMA information generation or updating function of a recording and reproducing apparatus which records information on or reproduces information from a disc with DMA information. The apparatus includes a test disc with test reference information; a reference drive generating test information from DMA of the test disc after the recording and reproducing apparatus performs reinitialization without certification using the test disc; and a verifier comparing reference information, which is expected from the test reference information, with the test information and providing the result of verifying the test information.